In U.S. Pat. No. 4,030,265, there is disclosed an arch beam comprised of a low modulus filler between a compression member and a tension member. Thus, the arch beam in said patent bears a superficial resemblance to the present invention. In said patent, the resistance of the compression member is increased by utilizing the compression strength of the low modulus filler. In said patent, the support points 20 and 21 are spaced apart by a distance which is smaller than the distance between the focus points. In said patent, reaction blocks 18 and 19 are utilized to distribute stress concentration from the reaction forces at the support points. The present invention is directed to a different class of structures from that disclosed in said patent.